#Units : g / mol

M = {
'O' : 15.9994,
'O2' : 31.9988,
'O3' : 47.998,
'CO' : 28.010,
'CO2': 44.01,
'SO2': 64.07,
'N2' : 28.0134,
'NO' : 30.006,
'NO2': 46.0055,
'CH4': 16.042,
'vapor': 18.0159,
'dry_air': 28.9644
}

